Method and apparatus for surface finishing



NOV. 15, 1955 KRAFFT 7 2,723,505

M PPARATUS FOR SURFACE FINISHING Filed May 25, 1955 M Q Mn 3 Sheets-Sheet 1 IWII 1 FIG-2 INVENTOR. FREDERICK G KRAFFT ATTORNEYS Nov. 15, 1955 KRAFFT METHOD AND APPARATUS FOR SURFACE FINISHING 3 Sheets-Sheet 2 Filed May 25, 1953 INVENTOR. REDERICK G. KRAFFT 7 bah ATTORNEYS Nov. 15, 1955 F. G. KRAFFT 2,723,505

METHOD AND APPARATUS FOR SURFACE FINISHING Filed May 25, 1953 5 Sheets-Sheet 3 IIII I/III/IIIII/I 11,.

FREERICK e. KRAFFT MW,

ATTORNEYS United States Patent METHOD AND APPARATUS FOR SURFACE FINISHING Frederick G. Kraift, Springfield, Ohio, assignor to The Thompson Grinder Company, Springfield, Ohio, a corporation of Ohio Application May 25, 1953, Serial No. 357,100

Claims. (Cl. 51-141) This invention relates to a method and apparatus for surface finishing, and particularly to such a method and apparatus for abrasive surface finishing in a manner to impart a surface pattern to the workpiece being operated.

This application is a further extension of the inventive thought disclosed and claimed in my co-pending application, Serial No. 308,265, filed September 6, 1952, and assigned to the same assignee as this application.

In my co-pending application I show an arrangement whereby an abrading member such as a grinding wheel is provided with a discontinuous working surface, either by a special manufacture of the wheel or by a special dressing technique, and which wheel is then utilized for imparting a spot pattern to a surface by rotating the wheel at a predetermined speed and passing the wheel over the surface of a workpiece at a predetermined relative speed. In this manner a spot pattern is imparted to the surface of such members as the ways of machine tool beds. This spot pattern imparted to the ways in this manner not only improves the appearance of the ways, but also provides for shallow depressions arranged according to a predetermined fixed pattern for retaining lubricant, by means of which proper and adequate lubrication of the ways is had at all times.

Due to the fact there is either a special manufacture of the wheel required or a special dressing of a standard wheel, the process of the invention in my co-pending application is subject to certain economical limitations. For example, where it is desired merely to provide a surface with ornamentation, as in the case of a saw blade or the like, a somewhat simpler and less expensive apparatus and a method somewhat simpler to carry out is indicated.

Having the foregoing in mind, it is a primary object of the present invention to provide a method and apparatus for surface ornamentation of work members by abrasion in a simple and inexpensive manner.

Another object of this invention is the provision of a method and apparatus for surface ornamentation by abrasion adapted for being incorporated in substantially any standard grinding setup.

A still further object is the provision of a method and apparatus for surface ornamentation by abrasion wherein no specially constructed or specially dressed grinding wheels are required.

A still further object of this invention is the provision of a method and apparatus for surface ornamentation by abrasion wherein the pattern of the ornamentation can readily be changed and in a relatively inexpensive manner.

These and other objects and advantages of this invention will become more apparent upon reference to the following specification taken in connection with the accompanying drawings, wherein:

Figure 1 is a perspective view of a substantially conventional grinding machine having a surface finishing mechanism according to my invention incorporated therein;

. abrasive belt at the bottom of roll 26, and then the table 2,123,505 Patented Nov. 15, 1955 Figure 2 is a perspective view, the device of the invention looking down from above and to one side thereof;

Figure 3 is a view like Figure 2 but showing a device looking up from beneath and to one side thereof;

Figure 4 is a fragmentary sectional view indicated by line 4-4 on Figure 3;

Figure 5 is a fragmentary sectional view showing a modified form which this invention can take;

Figure 6 is a view like Figure 3 but showing the appearance of the device with a supporting roll of a somewhat different character than is shown in Figure 1 through 4;

Figure 7 is a perspective view showing a roll according to this invention;

Figure 8 is a sectional view indicated by line 8-8 on Figure 7;

Figure 9 is a view like Figure 8 but showing a still further modified construction;

Figure 10 is an end elevational view of one form which the device, according to this invention, can take including an adjustable idler roll;

Figure 11 is a sectional view indicated by line 11i1 on Figure 1 and showing the mounting for one of the fixed idler rolls of Figure 10;

Figure 12 is a perspective view showing the adjustable mounting for the movable idler roll of Figure 10; and

Figure 13 is a perspective view showing how a substantially conventional flexible abrasive belt could be prepared for use in the practice of my invention by securing abrasive thereto according to a spot pattern.

Referring to the drawings somewhat more in detail, the grinding machine illustrated in Figure 1 comprises a bed 10 on which is reciprocably mounted a table 12. Hydraulic means not illustrated, but well known to the art, are provided for reciprocating the table on the bed, and the speed of reciprocation of the bed is adapted for being controlled by manual means located on the control panel 14.

Adjacent bed 10 is a column 16 carrying in vertical reciprocation a saddle 18 in which is movably mounted a wheel head 20 including a motor not shown that drives spindle 22.

The saddle 18 can be raised and lowered on column 16 toward and away from support 24 which is adapted for receiving a workpiece.

As will be seen in Figure 2, there is mounted on spindle 22 a roll, preferably a metal roll, 26 having raised por tions 28 on its periphery separated by the grooves 30., The raised portions 23 are in the form of a discontinuous pattern, whereas the grooves portion 30 of the roll is continuous.

Mounted on the wheel head in spaced relation with roll 26 are idler rolls 32, and passing about the three rolls is a flexible abrasive belt member 34.

As will be seen in Figure 3, around the bottom of roll 26 the raised portions 28 of the roll cause corresponding raised portions 36 to extend outwardly from the surface of the abrasive belt. This is also illustrated to an exaggerated degree in Figure 4. The material of the abrasive belt is preferably a strong fabric having an inherent degree of resilience, but it is conceivable that a paper could be employed, preferably one that had been sized or otherwise impregnated with a latex in order to provide for a degree of resilience that would permit the backing of the belt to yield sufiicient to provide for the raised portions 36.

In operation, the roll 26 is driven at the speed necessary to give the proper surface speed to the abrasive belt to accomplish the grinding action desired. The workpiece to be treated, designated as 38 in Figure 2, is then brought into proper working alignment with the surface of the 12 is actuated to carry the work member across once beneath the roll. The speed of the work member at this time is such that the spot pattern, designated at 40 in Figure 2, is imparted thereto.

It will be understood that this spot pattern could vary widely and could be in the form of a continuous or discontinuous pattern of spots, and that it would be on the order of a very shallow configuration.

By the practice of this invention workpieces cannot only be enhanced in appearance but slight irregularities in the surface thereof can be made to disappear so that work members which might formerly have been seconds will now become a first class product.

The arrangement just described utilizes a simple arrangement of a formed metallic roll and a conventional sanding belt. According to the modification of Figure 5 there is shown a belt 42 of resilient material such as impregnated fabric having raised portions 44 thereon to which there is secured by a suitable adhesive means the abrasive 46. The belt could also be a conventional abrasive belt having the abrasive arranged thereon in a pattern. The belt of Figure 5 can be utilized with a smooth supporting roller, and when worn down beyond the point of usefulness, it can be renewed by again building up the abrasive on the raised portions 44 thereof.

With the arrangement described previously it has been presumed that the workpiece was brought to the step of surface configuration in a finished condition. However, it may be desirable to provide for an overall finish abrading of the work member simultaneously with the abrading thereon of the surface configuration according to this invention, and arrangements are shown for accomplishing this in Figures 6 through 9.

Referring first to Figure 6, which is similar to Figure 3, it will be noted that the belt 34 has no raised portions projecting therefrom where it passes about the roll 48. This comes about because the rolls are constructed as illustrated in Figure 7 so as to have the raised portions 50 with the grooved spaces between the raised portions being filled with a resilient rubberlike material 52. The raised portions 50 in Figure 7 are of a different configuration than those previously described and are illustrated in this manner merely to indicate the diversity that can accompany the spot pattern imparted to a workpiece according to this invention.

The action that obtains when utilizing the rolls of Figures 6 and 7 is illustrated in Figure 8 wherein it will be observed that the abrasive belt 34 is pressed down hard against workpiece 38 at the raised portions 56 of the roll, but is only resiliently pressed down by the rubberlike material 52 between the said raised portions. In this manner an overall finishing of the surface takes place, but at the portions of the workpiece where the raised portions of the roll have been effective a definite and regular surface configuration will be imparted to the work memher.

This general idea can be carried still farther, as illustrated in Figure 9, wherein the raised portions 50 not only have resilient material 52 therebetween, but there is also a resilient layer 54 covering the entire outer periphery of the roll.

In the Figure 9 arrangement the different degree of resilience of the backing up roll between the raised portions 50 and the spaces therebetween is effective for imparting the desired pattern to the workpiece being treated.

As a convenient manner of mounting a device according to this invention on the wheel head of a substantially conventional grinding machine, there may be provided a mounting plate 60 carrying the idler rollers with the plate being attached to the wheel head as by the cap screws 62. Preferably, the shafts 64 on which the idler rollers are journalled are threaded into the wheel head as illustrated in Figure ll, and serve not only to provide additional support for the plate but also provide a firm support for the idler rollers.

In the Figure 10 arrangement an auxiliary tensioning roll 66 is provided mounted on a shaft 68 which, as will be seen in Figure 12, is carried by a block 70 vertically slidable in a slot in a block 72 that is fixed to plate 60. An adjusting screw 74 is provided for effecting adjustment of block 70 whereby any desired tension can be maintained on the abrasive belt.

In all of the modifications described, with the exception of the Figure 5 modification, a conventional abrasive belt is employed with a formed back up roll. The roll being subjected to no wear will last indefinitely, while the abrasive belt, inasmuch as it will engage the back up roll differently on each revolution, can be employed until the entire abrading surface thereof has been exhausted.

In the Figure 13 arrangement there is shown a flexible resilient belt having thereon the abrasive spots 82 with spaces 84 between the spots which do not contain abrasive. In the particular arrangement illustrated in Figure 13 the spots of abrasive are not connected where as the non-abrasive spots are connected, but it will be understood that the Figure 13 modification, as in connection with any of the other modifications, could be arranged so that the abrasive pattern is connected and the nonabrasive pattern in that case would consist of individual spots. in general, it is to be preferred for the abrasive spots to be interconnected, particularly when the pattern abraded on the work member is for the purpose of retaining lubricant, but where the pattern imparted to the work member is principally for the purpose of surface ornamentation it may, at times, be preferable for the abrasive areas to be connected in the manner referred to.

By the practice of the present invention the necessity for expensive wheel constructions is eliminated, as well as the neceessity of a special dressing operation being carried out on a wheel or a grinding machine being provided with an auxiliary spindle on which a special wheel is mounted.

The present invention, in particular, provides an inexpensive and convenient means for the surface finishing of work members such as saw blades and the like in which the visual character of the finished surface is more important than the physical character.

It will be understood that this invention is susceptible to modification in order to adapt it to different usages and conditions, and, accordingly, it is desired to comprehend such modifications within this invention as may fall within the scope of the appended claims.

I claim:

1. A method of surface finishing a work member to provide the same with a predetermined fixed pattern, said method comprising abrading said work member which comprises; moving an endless flexible abrading belt at grinding speed, traversing the belt and the work member relatively at a predetermined speed in one direction only, and engaging the entire surface to be finished by said belt whereby an overall abrading of the surface is had, pressing spaced areas of the belt against the work member at a different pressure than the other areas of the belt whereby the abrading of the surface is non-uniform and a spot pattern is imparted to the work member, and moving the said work member only once beneath and in abrading contact with said abrading belt to provide the work member with a surface pattern finish.

2. In a machine for finishing a work member to provide the same with a predetermined fixed pattern abraded into the surface; a work member support, a roll adjacent said support, means for supporting an abrasive belt so that it passes about said roll, means for driving said belt and roll at grinding speed and for traversing the roll and work member support relatively a single time and at a predetermined speed for a complete abrading operation, and means comprising spaced portions on said roll which are hard and substantially unyielding projecting radially and being uniformly spaced thereon axially and circumferentially of said roll, resilient material disposed between said hard portions, said last-mentioned portions imparting a predetermined and regular spot pattern to the surface of the Work member being finished by causing corresponding portions of said belt to abrade the work member differently than portions of said belt between said projecting portions of the roll.

3. In a machine for finishing a work member to provide the same with a predetermined fixed pattern abraded into the surface; a work member support, a roll adjacent said support, means for supporting an abrasive belt so that it passes about said roll comprising idler rollers mounted on axes parallel with the axis of said roll, means for driving said roll and belt at grinding speed and for traversing said roll and work member support relatively a single time and at a predetermined speed for a complete abrading operation, said roll comprising a plurality of hard and substantially unyielding radially projecting portions arranged in substantially spaced relation in a predetermined pattern for causing the portions of the belt engaged thereby to abrade a spot pattern on the surface of the work member being finished, grooved spaces between said hard portions, said grooved spaces between said raised portions being filled with a resilient composition.

4. In a machine for finishing a work member to provide the same with a predetermined fixed pattern abraded into the surface; a work member support, a roll adjacent said support, means for supporting an abrasive belt so that it passes about said roll comprising idler rollers mounted on axes parallel with the axis of said roll, means for driving said roll and belt at grinding speed and for traversing said roll and work member support relatively a single time at a predetermined speed for a complete abrading operation, said roll comprising a plurality of hard and substantially unyielding radially projecting portions spaced a substantial distance apart and arranged in a predetermined pattern for causing the portions of the belt engaged thereby to abrade a spot pattern on the surface of the work member being finished, grooved spaces between said hard portions, said grooved spaces between said raised portions being filled with a resilient rubber-like composition, and there being a thin layer of resilient composition extending over the entire periphery of said roll.

5. In a machine for finishing a work member to provide the same with a predetermined fixed pattern abraded into the surface; a rigid roll, idler rollers adjacent said roll, a flexible abrasive belt passing about said roll and rollers, and said roll comprising uniformly axially and circumferentially spaced radially projecting integral portions of uniform configuration, and which are hard and substantially unyielding, grooved spaces between said projections, said spaces being filled with a resilient material so that said roll is normally cylindrical but will be deformed at least slightly upon the application of pressure thereto when it is brought into engagement with a work member.

References Cited in the file of this patent UNITED STATES PATENTS 794,496 Gorton July 11, 1905 875,936 Landis Jan. 7, 1908 1,988,065 Wooddell Jan. 15, 1935 1,995,382 Fenton Mar. 26, 1935 2,002,666 Johnson et a1. May 28, 1935 2,019,889 Breed Nov. 5, 1935 2,115,897 Wooddell et al May 3, 1938 2,162,279 Herchenrider June 13, 1939 2,407,939 Steinhilber Sept. 17, 1946 2,431,822 Murray Dec. 2, 1947 2,447,602 Herchenrider Aug. 2, 1949 2,555,317 Chaplin June 5, 1951 2,581,270 McVey Jan. 1, 1952 2,605,592 Cosmos Aug. 5, 1952 FOREIGN PATENTS 831,648 Germany Dec. 29, 1950 

